Appeals made by Cook's defense team were denied by a state board for the final time on August 3, and by the U.S. Supreme Court before his execution earlier this morning.

Cook was executed at 11:03 a.m today, after a lethal-injection process that began at 10:26 a.m.

"I'd like to say sorry to the victim's family. I know that's not enough," Cook said as he gave his last words, according to the Arizona Department of Corrections. "Where am I? To my lawyers, thank you. Red Robin, yum. I'm done. I love you".

At the time of the murders, Cook, Cruz-Ramos, and another man named John Matzke shared an apartment together.

One day, Cruz-Ramos confronted Cook and Matzke about $90 he said Cook stole from him. Matzke and Cook subdued Cruz-Ramos, then sodomized, tortured, and strangled him to death, according to a report released by the DOC.

The other victim, Swaney, came by the apartment around this time, and was shown Cruz-Ramos' body. Cook then sodomized Swaney and strangled him to death.

Matzke confessed to his involvement in the murders and accepted a plea bargain for a 20-year prison sentence for his cooperation in helping bring in Cook.

Some controversy arose over his execution, because a psychological and emotional evaluation of Cook shows that he suffered from serious mental trauma. That mental trauma stems from the horrific abuses he suffered as a child.

Cook was abused from infancy all the way through most of his teenage years. His parents, grandparents, step-father, step-brothers and foster parents physically and sexually abused him on countless occasions, according to a clemency report submitted for Cook's appeal.

Among the many abuses Cook endured growing up included his father's burning his penis with a cigarette when he was an infant, rape and molestation by his mother and grandparents, and a group-home leader's forcing him to undergo circumcision when he was 15.

That wasn't the only strange thing the group-home leader did to Cook.

"There was a 'peek-a-boo room' which was used for 'time outs,'" according to the report. "This room had a one-way mirror and Dan, along with other boys, would be subjected to abuse while adults watched from the other side. Dan was forced to spend time in the 'peek-a-boo room,' naked and handcuffed to the bed, while [the group leader] would rape him."

The report argued that the gruesome experiences Cook lived through as a child caused him to develop post-traumatic-stress disorder. He also suffered brain damage as a child, because his mother was negligent and used drugs and alcohol during her pregnancy. These factors, coupled with Cook's own struggles with drug addiction, led to his monstrous behavior, his attorneys contend.

The appeal acknowledged that Cook should be punished for his crimes but maintained that he should not be put to death because he wasn't in full control of his actions.

Many of the same injuries and methods of torture carried out by Cook in the heinous murders of his victims matched the abuses Cook received as a child. Cook burned the genitals of Cruz-Ramos with a cigarette, sodomized him, then crushed his throat with a metal pipe, according to the DOC report.

Cook's defense team appealed the death sentence on grounds that Cook was legally misrepresented during his trial. He represented himself originally -- and asked the court to give him the death penalty, according to the clemency report. He said he was shocked that he could've committed such a horrific crime.